Conical scan attenuator



Nov. 14, 1961 H. GALLAY ETAL CONICAL SCAN ATTENUATOR 2 Sheets-Sheet 1 Filed July 8, 1955 JOMRRQQ INVENTORS HARRIS GALLAY BY WILLIAM D. COHEN mos-SEE? 23m #228 A TTORNEYS 2 Sheets-Sheet 2 INVENTORS HARRIS GALLAY WILLIAM D. COHEN t1 TTOBNEXQ Nov. 14, 1961 H. GALLAY ETAL CONICAL SCAN ATTENUATOR Filed July 8, 1955 United States Patent 3,009,122 CONICAL SCAN ATTENUATOR Harris Gallay, Belleville, N.J., and William D. Cohen, Brooklyn, N.Y.; said Gallay assignor to the United States of America as represented by the Secretary of the Navy Filed July 8, 1955, Ser. No. 520,646 12 Claims. (Cl. 333-81) This invention relates to improvements in wave generating means and more particularly pertains to improvements in scan attenuators for wave guides.

The generation of a sine wave by means of a rotating disc that enters into and leaves a wave guide through a slot in such wave guide is accomplished by having the disc function as an attenuator. By coupling the disc to a positioning means that stops and locks the disc in a zero attenuating position when the disc is not being used, and by the use of a latching mechanism coupled mechanically to the solenoid armature of a relay of an actuating switch, full motor torque at low speed can be derived, and other advantages hereinafter described can be realized.

The principal object of this invention is to provide an improved scan attenuator for wave guides.

Another object is to provide a device adapted to generate a sine wave by means of a rotating disc attenuator coupled to a positioning means that stops and locks the disc in a zero attenuating position when the disc is not being used.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the followmg detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a simplified schematic diagram of a conical scan attenuator, showing a preferred embodiment of the invention; and

FIG. 2 is an exploded view of the conical scan mechanism.

Similar numerals refer to similar parts throughout the several views.

In a preferred embodiment of the invention, a wave guide 11 is provided with a slot 13 adapted to pass a Cbnical scan attenuator disc 15. Said disc 15 is a phenolic resistance card material from which a segment has been cut to provide a peripheral flat 17. The attenuation introduced in the wave guide 11 by said disc thus can vary as a sine wave with rotation of said disc, one sine wave cycle occurring with each revolution.

In the conical scan-off condition, said disc 15 is held locked in zero attenuation positioned by latching mechanism hereinafter described. Such latching mechanism is coupled mechanically to the solenoid armature 19 of a relay 21.

As shown in FIG. 2, bracket 41 comprises a pair of Wall members 43 and 45 bridged by mounting plates 47 and 49. A tachometer generator 51 is mounted on plate 47 and is provided with a sprocket gear 53. The circuit of said generator can include a multiplier resistor 54 and a meter 56 adapted to be paralleled with generator 51 by switch 58. Chain 55 couples gear 53 and sprocket drive gear 57 of motor 27, which is also mounted on plate 47 and includes a rotor shaft 59. Flange 61 and retainer 63 sandwich disc 15 for drive by said shaft.

Mounting plate 69, which is secured on plate 49 by a plurality of retaining means, as shown, includes lugs 71 that carry a roll pin 73 on which trip arm 75 is carried rotatably. Said trip arm has a bore 77 in a first leg 79 to receive pin 73, a slot 81 in a second leg 83 to receive roll pin 85 rotatably and translatably and a pair of hardened steel latch teeth 87 and 88.

Latch member 65, secured with drive gear 57 on shaft 59, is a circular member partially cut away at the left side (as viewed in FIG. 2) to form a shoulder 66. The latch member 65 is also formed with a second excised section 67 in the form of a sector or wedge located at the right side of center. The lower edge of this excised sector 67 is parallel to the shoulder 66 and lies at a distance beneath the shoulder 66 equal to the thickness of the hardened steel teeth 87 and 88. The face of the latch member 65 is preferably hardened.

The latch teeth 87 and 88 are in a position to engage the lower edges 67 and 66, respectively, of the excised sector and the shoulder when the trip arm is forced against the face of the latch member 65 by the action of the coil spring 35. This engagement of the teeth 87 and 88 locks the motor shaft 59 so that the attenuator disc 15 is completely out of the wave guide 11.

The relay 21 comprises a frame 89 secured on plate 69, a spool member 91, base 93 and terminal board 95. The armature head 37 carries bracket 97, which is provided with upstanding lugs 99 bored to receive roll pin 85. The sensitive switch 39 is so mounted on plate 69 that the actuating pin 101 thereof is aligned axially with armature 19. When armature l9 rises and tooth 87 enters the excised sector 67, pin 101 is released and opens switch 39 which, in turn, opens the motor circuit. Latch member 65 and trip arm 75 remain meshed and lock the motor shaft as long as the conical scan control is in the off position. When this control is turned on again, the solenoid 2.1 becomes energized, its armature 19 retracts and frees the motor shaft locking mechanism, switch 39 is actuated and the motor is energized through resistance 23.

Referring to FIG. 1, resistance 23 is a control rheostat functioning as an armature series resistor. The moving arm of said resistance 23 is coupled to mechanically operate a double pole double throw switch 25 in such manner that, when the resistance 23 is turned to its maximum value (corresponding to its low speed end position), it forces switch 25 into its 0 position. (Switch 25 is shown in its off position in FIG. 1.) When the moving arm of the resistance 23 is turned to its minimum value, it forces switch 25 into its on position, thereby applying 28 volts to energize the conical scan motor 27 through the resistances 23 and 29. Between the off and on extremes, the moving arm of rheostat 23 can insert a variable amount of resistance in the scan motor circuit, thereby varying its rotational speed.

Activation of the switch 25 to its off position m0- mentarily restores full power to conical scan motor 27, because resistance 23 and resistance 29 (a fixed series resistor to limit maximum current through the motor armature) are both shorted by the lower switch arm 31. The torque of motor 27 thus increases and the rotor thereof tends to accelerate from its minimum speed. At the same time, the upper switch arm 33 has opened the circuit of control solenoid 21, and its armature 19 will tend to rise from the solenoid coil assembly due to the force exerted by coil spring 35 built into the head 37 of armature 19.

The rising armature 19 forces the teeth 87 and 88 of the trip arm 75 against the face of the latch member 65. This results in added friction which is compensated for by the increased torque of motor 27 resulting from the shorting out of resistor 29 and rheostat 23 when switch 25 is turned to its off position. The motor 27 is de-energized by the opening of sensitive switch 39 when the pressure of the solenoid armature 19 against pin 101 is released by engagement of the latch teeth 87 and 88.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

We claim:

1. Wave generating means comprising a wave guide, an attenuator disc coupled to enter and leave said wave guide to introduce a sinusoidal attenuation within said wave guide, a shaft coupled to rotate said attenuator disc, a motor coupled to rotate the attenuator disc through the shaft, a sleeve member afiixed to said shaft and formed with excised sections therein, a solenoid having a spring loaded armature, a latch lever mechanically connected to said armature and insertable in said excised sections in said sleeve member to lock said sleeve member in a predetermined position and a switch mechanically coupled to said armature and electrically coupled to said motor to control the flow of current to the motor.

2. Wave generation means comprising a wave guide having an attenuator disc slot, an attenuator disc adapted to rotatably enter and to withdraw fully from said wave guide through said slot, motor means to rotate said disc through repetitive entries and withdrawals, means to lock said motor means to retain said disc in a predetermined fixed position, and means to momentarily restore substantially full torque to said motor means immediately prior to said locking of said motor means, said restoration of torque being effected in order to prevent cessation of rotation of said disc clue to friction effects before positive locking of the disc in said predetermined fixed position can occur.

3. In combination with wave generating means including a wave guide formed with a slot in one wall thereof, wave modulating means comprising, in combination: a modulating member arranged to rotatably enter and leave said slot; means to rotate said modulating member including shaft means to which said modulating member is secured; means to automatically stop the rotation of said modulating member at a predetermined fixed point in its rotational cycle comprising a first member secured to said shaft and formed with excised sections therein and a second member arranged to be inserted in said excised sections for engagement with said first member; and means to automatically insert said second member in said excised sections.

4. In combination with wave generating means including a wave guide formed with a slot in one wall thereof, wave modulating means comprising, in combination: a modulating member arranged to rotatably enter and leave said slot; means to rotate said modulating member including shaft means to which said modulating member is secured; means to automatically stop the rotation of said modulating member at a predetermined, fixed point in its rotational cycle comprising a first member secured to said shaft and having a face formed with excised sections therein and a second member arranged to be forced against said face and into said excised sections for engagement with the sides of said excised sections; and means to automatically force said second member against the face of said first member at a selectable time.

5. In combination with wave generating means including a wave guide formed with a slot in one wall thereof, wave modulating means comprising, in combination: a modulating member arranged to rotatably enter and leave said slot; means to rotate said modulating member including shaft means to which said modulating member is secured; means to automatically stop the rotation of said modulating member at a predetermined, fixed point in its rotational cycle comprising a first member secured to said shaft and having a face formed with excised sections therein and a non-rotatable second member arranged to be forced against said face and into said excised sections for engagement with the sides of said excised sections; and means to automatically force said second member against the face of said first member at a selectable time.

6. In combination with wave generating means including a wave guide formed with a slot in one wall thereof, wave modulating means comprising, in combination: a modulating member arranged to rotatably enter and leave said slot; means to rotate said modulating member including shaft means to which said modulating member is secured; means to stop the rotation of said modulating member at a predetermined point comprising a first memer secured to said shaft and having a face formed with excised sections therein and a non-rotatable second member arranged to be forced against said face and into said excised sections for engagement with the sides of said excised sections; and means to force said second member against the face of said first member comprising switch means having an on and an off position and a solenoid in circuit therewith, said solenoid having a springbiased armature mechanically coupled to said second member whereby, when said switch means is placed in its off position, said armature is actuated by said spring to force said second member against the face of said first member.

7. Wave modulating means as set forth in claim 6, including resistive means in circuit with said means to rotate said modulating member, said switch means arranged to include said resistive means in the energization circuit of said rotative means when placed in its on position and to remove said resistive means from the energization circuit of said rotative means when placed in its off position, said removal of said resistive means from said energization circuit acting to increase the torque developed by said rotative means.

8. Wave modulating means as set forth in claim 7, including circuit-breaking means mechanically coupled with said solenoid armature and arranged to break the energization circuit of said rotative means when said second member is inserted in said excised sections of said first member.

9. Wave modulating means as set forth in claim 8, wherein said first member is a sleeve-like member whose aforementioned face is fiat and substantially circular, said excised sections are at least two in number, one on each side of center of said face, and said second member is formed with at least two projections thereon shaped to fit into said two excised sections.

10. A device to lock a rotating member at a predetermined point in its rotational cycle comprising, in combination, a driven member, means to rotate said driven member including shaft means to which said driven member is secured, means to automatically stop the rotation of said driven member at a predetermined, fixed point in its rotational cycle comprising a first member secured to said shaft and having a face formed with excised sections therein and a non-rotatable second member arranged to be forced against said face and into said excised sections, and means to automatically force said second member against the face of said first member comprising switch means having an on and an off position and a solenoid in circuit therewith, said solenoid having a spring-biased armature mechanically coupled to said second member whereby when said switch means is placed in its off position, said armature is actuated by said spring to force said second member against the face of said first member, resistive means in circuit with said means to rotate said driven member, said switch means arranged to include said resistive means in the energization circuit of said rotative means when placed in its on position and to remove said resistive means from the energization circuit of said rotative means when placed in its off position, said removal of said resistive means from said energization circuit acting to increase the torque developed by said rotative means.

11. A device as set forth in claim 10, including circuitbraking means mechanically coupled with said solenoid armature and arranged to break the energization circuit of said rotative means when said second member is inserted in said excised sections of said first member.

12. A device as set forth in claim 11, wherein said first member is a sleeve-like member whose aforementioned face is flat and substantially circular, said excised sections are at least two in number, one on each side of center of said face, and said second member is formed with at least two projections thereon shaped to fit into said excised sections.

References Cited in the file of this patent UNITED STATES PATENTS Broomhead Aug. 10, Hansch et a1 Nov. 8, Lyman Apr. 25, Grant Nov. 25, Hatcher Oct. 9, Richards Sept. 8, 

